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MXenes as a new family of two-dimensional (2D) materials have attracted increasing attention recently because of their outstanding physical and chemical properties and versatile applications, especially in energy storage and catalysis. This review will focus on the catalytic properties of MXenes and their application in electrocatalysis. In particular, we shall systematically discuss their applications into electrical-driven hydrogen production, solar-driven hydrogen production, and nitrogen reduction. This review provides an insightful understanding on the mechanism behind the outstanding performances observed in experiments and calculations, which may guide the design of novel catalysts with high catalytic activities in electrocatalysis. Additionally, a wide range of strategies to design and fabricate new MXenes as electrocatalysts will be discussed to give potential avenues for their commercial applications. Finally, the perspective on the future development is given in the end.

Maintenance is important for the service of products and it is different from repair because repair focuses on the time node when the products break down, which is a qualitative problem, but maintenance pays more attention to the continuity of machine’s work, and thus it is not a qualitative problem. Nevertheless, almost all the study methods are of qualitative methods because they only qualitatively divided the health state of machines into several levels, which are not fit to comprehensively explore the degradation principle of machines and the relationship between degradation and maintenance. To discover the degradation principle of machines influenced by maintenance, a quantitative study method is proposed by calculating the Health Index (HI) based on fuzzy analytic hierarchy process (FAHP) and convolutional neural network (CNN). Finally, a case study is used to demonstrate the implementation and potential applications of the proposed method, in which two major maintenance methods in prognostic and health management (PHM), i.e. time-based maintenance (TBM) and condition-based maintenance (CBM) are studied. The results show that the application of the proposed method leads to a significant increase in the life of machines. This study puts forward a new method to study the degradation principle of machines and will lead to the development of PHM using the HI.

Two-dimensional (2D) materials attract enormous attention and show promising applications in many fields of science and technologies (nanodevices, energy storage/harvest and catalytic processes, etc.). Pentagonal compounds emerge as a new family in 2D materials along with classic trigonal transition metal dichalcogenides and MXenes, which have been intensively investigated to date. Encouraged by the successful synthesis of pentagonal PdSe2 using CVD method, we explore nine pentagonal monolayers, MX2 (M = Ni, Pd & Pt, and X = S, Se & Te), based on the first-principles calculations. We find that all MX2 are dynamically and thermodynamically stable, and intrinsic semiconductors. Our results show that PdTe2 exhibits excellent potential application in solar water splitting due to optimal band gap and suitable band-edge positions matching with both the water reduction and oxidation potentials (0 and 1.23 V vs. NHE). We further find that the majority of MX2 monolayers (except NiTe2) are applicable in photocatalytic oxygen production. Our findings are expected to shed light on the possible synthesis of pentagonal MX2 and their application in photocatalytic water splitting.

This article presents a closed-loop Kaizen system with discrete event simulation in the stage of design and reengineering of mass-customization production system. This approach contains four steps: current process analysis, production line design, discrete event simulation to solve the dynamic event questions, and implements and evaluation. The current process analysis and the production line design refer to the value stream mapping and the productivity analysis based on Kaizen principle, respectively. Production line designs are the modeling basis of discrete event simulation, and discrete event simulation feeds back results to the decision-makers to reduce waste and cost and improve the quality and productivity by reforming the production line. Therefore, by connecting the closed-loop Kaizen with discrete event simulation, the production line can be continuously and automatically improved. To demonstrate the potentials of the closed-loop Kaizen system, a case study was applied based on the original production layout and economic benefits were achieved. Moreover, this article indicates a direction for the full automation of process optimization.

Hydrogen production via water splitting is considered to be one of the most promising technologies in the future hydrogen economy, where the critical challenge in this technology is exploring high-...

Efficient and abundant electrocatalysts are very important for practical hydrogen evolution from the electrocatalysis of water on large-scale. Therefore, it is necessary to study the intrinsic elec...

With the continuous improvement of living standards, customers are gradually pursuing products which are individualization and entertainment. The traditional large-scale manufacturing mode cannot meet the individual needs of customers. The production mode of the enterprises has been changed from the traditional inventory mode to the customization manufacturing mode driven by the customer orders. Furthermore, the simple customization model cannot meet the industrial needs in the open and networked era. Therefore, there is a lack of an innovative manufacturing mode that not only meets the individual needs of customers, but also adapts to today’s open and networked environment. In this paper, a new customization model was proposed, which is a continuously improved customization model called CPMS (Customer Platform-connection Manufactory to Service). By means of research methodology of literature review and analysis, the birth, concept, and evolution of CPMS in PSS are discussed. Through analysing the development of industry, combining with the existing analysis and projects we involved in, and the method of system engineering analysis, an overall framework of CPMS model is derived. At last, a case study for implementation of CPMS in the car industry has been given. Under this model, enterprises can improve the flexible production capacity of production line, reduce the production cost, reduce inventory, improve the modular configuration of products, and etc. Moreover, it can provide some reference value for enterprises to plan, design, implement and apply a new customization production model that conform to the requirements of the new era of open and networked.

In the current trend of smart manufacturing, the architecture of smart manufacturing is gradually proposed by many countries in the world. Main components, elements, functions, and relationships of these smart manufacturing architectures have been clarified. However, the specific details of cross matching of different dimensions in these smart manufacturing architectures have not been thoroughly developed. Therefore, a certain part of a plane intersected of system hierarchy dimension and smart characteristics dimension in the model for smart manufacturing (SMS) from a perspective of implementation was selected for detailed study, which is defined as smart manufacturing implementation system (SMIS). Firstly, a top-level scenario planning of SMIS was proposed from perspectives of lean factory, interconnection factory, information factory, transparent factory, virtual factory, and smart factory. Then, an overall framework of SMIS was deduced through a top-level scenario planning of SMIS. Finally, through a case study, the specific implementation process of SMIS is obtained. Through the proposed overall framework and implementation path of SMIS, enterprises can implement intelligent manufacturing step by step. In addition, the top-level scenario planning and overall framework of SMIS are complementary to the SMS proposed by China.

With the continuous improvement of living standards, customers are ever more looking for products which are characterized by individualization, entertainment and scene. The production model of the enterprises is moving from the traditional inventory model to the manufacturing model driven by the customer orders. In this paper, we have summarized the birth, concept, characteristics, classification, evolution, related technologies and application of C2B (Customer to Business) models. Through the analysis of C2B which is based on e-commerce, mass customization and mass personalization, we have summarized and redefined the several forms of C2B: such as Customer to Business to Manufactory- Mass Customization (C2B2M-MC) model, Customer to Business to Manufactory- Mass Personalization (C2B2M-MP) model, Customer to Manufactory (C2M) model, CPM (Customer Platform-connecting Manufactory) model, Customer to Manufactory to Service (C2M2S) model, and have made a comparative analysis on these models. Finally, the implementation stages were proposed and effects of C2B were summarized. In addition, in the prospect of subsequent research, combining with the existing analysis and C2B projects we involved in, we will derive an overall framework of C2B. The research theory of this paper can give a certain reference to enterprises in the new period from the traditional mode to the network innovation mode. At the same time, it also has a good implementation effects in the related C2B projects we have participated in.

In this article, an integrated method is proposed for evaluating the requirements of smart manufacturing systems under the era of Industry 4.0 and Industrial Internet of Things. This method uses systematic research on identifying, classifying, and evaluating the requirements of smart manufacturing systems with uncertainty, multi-users, and multi-disciplines. The results of this article provide a procedure to capture the preferential SMSs-R and the framework of SMSs-R. First, this method provides a comprehensive requirement of smart manufacturing identified by questionnaire survey, document reviews, and the affinity diagram method. Second, the classification of SMSs-R considers the multi-user preference by the fuzzy Kano model. Third, the best non-fuzzy performance and fuzzy analytic hierarchy process method is used for evaluating and ranking the SMSs-R factor to solve the uncertain, vague, and preferential questions. Finally, we validated the effectiveness of the method through a real discrete manufacturing enterprise case.

In the tide of smart manufacturing in the world, many countries have put forward their own reference frameworks for smart manufacturing system. Based on the framework of smart manufacturing system (SMS) proposed by China, a reference smart manufacturing integration system (SMIS) from multi-level and multi-perspective was proposed. The reference model of SMIS was analyzed by means of system engineering. Based on this model, the overall architecture of SMIS was proposed. Then, the physics subsystem, information integration subsystem, network integration subsystem, data integration subsystem, and visualization integration subsystem for SMIS were proposed through the overall architecture of SMIS. Finally, the above integrated subsystems were collected together to deduce the implementation path of SMIS. Four reference subsystems for SMIS proposed in this paper have achieved good effects in the projects we participated in, which were organized by the state. The research results of this paper can be used as a reference for industry and government to design, set, and carry out SMIS. At the same time, it has a certain reference value for the improvement and supplement of national smart manufacturing system architecture.

A novel and highly active vanadium self-intercalated C/V1.11S2 nanosheets with abundant active sites are fabricated by a simple hydrothermal-calcinations method. The structures and morphology of C/V1.11S2 nanosheets were characterized by XRD, SEM, XPS and TEM. Particularly, PVP (polyvinylpyrrolidone) was used as surfactant to control the morphology of vanadium sulfide and carbon source to reduce the vanadium sulfide into vanadium self-intercalated V1.11S2 phase with rich active sites. The C/V1.11S2 nanosheets showed an excellent electrocatalytic activity for hydrogen evolution reaction, including a low onset potential of 15 mV vs. RHE (reversible hydrogen electrode), small Tafel slope of 51 mV dec−1, as well as extraordinary catalytic stability. The first-principle calculations further confirmed that the V1.11S2 has a much lower Gibbs free energy for hydrogen adsorption (ΔGH) than that of VS2. The enhanced HER performance can be contributed to the unique vanadium self-intercalated structures, nanostructured morphology and rich sulfur defects of the obtained C/V1.11S2 nanosheets. We believe that the C/V1.11S2 can be used as electrocatalyst in chemical engineering industry and our method provides guidance on the fabrication of other defective transition-metal dichalcogenides to improve their catalytic performances.

Enterprise information systems play a significant role in the Industry 4.0 era and are the crucial component to realize smart manufacturing systems. However, traditional enterprise information systems have some limits: (1) lack of complete information, (2) only satisfy limited business needs, and (3) lack of seamless integration, business intelligence, value-driven processes, and dynamic optimization. Clearly, the existing enterprise information systems are unable to satisfy the requirements for smart manufacturing systems: (1) autonomous operation, (2) sustainable values, and (3) self-optimization. In addition, smart manufacturing systems have become more efficient and effective, demanding for seamless information flow in enterprise information systems, knowledge, and data-driven accurately decision. Therefore, a new enterprise information systems framework is needed to bridge gaps between the requirements for traditional manufacturing system and smart manufacturing system. In this article, the integrative framework is proposed based on the business process reengineering, lean thinking, and intelligent management methods, with inclusion of six enterprise information systems aspects to provide upgrading guidelines from traditional manufacturing to smart manufacturing. The procedure of this method contains three steps: (1) it identifies requirements and acquires best practices using AS-IS model, (2) it redesigns six aspects of enterprise information systems using TO-BE model, and (3) it proposes a new enterprise information systems framework. Finally, the proposed framework is validated by real cases.

Highly efficient, earth-abundant, and low-cost photocatalysts are widely pursued for solar-driven hydrogen generation from water. Herein, we first report vanadium disulfide (VS2) with high hydrogen evolution reaction (HER) activity both in basal and edges to be the co-catalyst of graphitic carbon nitride (g-C3N4) for ultrahigh solar-driven hydrogen production. VS2-decorated g-C3N4 shows an impressing photocatalytic hydrogen evolution with a rate of 87.4 μmol/h, 26 times higher than pristine g-C3N4. Our combined experimental and computational studies reveal that the excellent efficiency of the composite is attributed to: (1) effective electron-hole separation and electron transfer from g-C3N4 to VS2, resulting from the optimal band alignment between VS2 and g-C3N4 and metallic characteristic of VS2; (2) fast hydrogen generation on the surface due to the high surface area and excellent HER activity of VS2. Our findings demonstrate that VS2/g-C3N4 may be applicable in solar-driven water splitting, and the design principle can be applied to search for novel photocatalysts.

Efforts will be made to improve the innovative design capabilities of advanced manufacturing industries and strategic emerging industries. Major breakthroughs will be made in key technologies and system integration innovation capabilities in the fields of electronic information, high-end equipment, new energy, new materials, aerospace, rail transportation, energy conservation and environmental protection.

Graphene has been widely studied as an electrocatalyst for hydrogen evolution reaction (HER). However, pure flat graphene is catalytically inert in HER. In this work, we investigate the effect of curvature on the improvement in the catalytic activity of pure and doped graphenes. We find that the HER performance can be dramatically improved on waved-graphene due to localized chemical potential and Pt-analogous activity can be achieved at suitable compression. (1) For pure graphene, the calculated HER performance increases more than 50% as tuned by curvature due to reduced calculated Gibbs free energies. (2) For B- and N-doped graphene, their optimal HER catalytic ability occurs at low curvature conditions. (3) For metal-doped graphene, Mo-doped graphene exhibits excellent catalytic ability in HER at certain compressions. (4) For nitrogen-metal co-doped graphene, N–Ni and N–V co-doped graphenes can be tuned by curvature to show outstanding performance in HER with their exothermal formation energies. Our cal...

The quality of solder paste deposition (SPD) mostly decides performance of solder joints between system on a chip and printed circuit board. In view of the complexity of this SPD process, identifying the key process parameters and optimizing them are very important to improve the quality of SPD. Based on different products maybe having different key process parameters, the cause-and-effect matrix tool was employed to identify the key parameters (squeegee pressure, squeegee speed, and separation speed) and multiresponse (volume, area, height, and offset) of this paper. The hybrid approach integrating Taguchi–Grey relational analysis and entropy was used to convert multiobjective quality characteristics of SPD into a single-objective grey relational grade. Entropy was used to measure importance weight of volume, area, height, and offset. With estimated grey relational grade, it was confirmed that the optimum parameter level combination were better than the production parameter settings. The analysis of variance indicated the parameter of separation speed was most significant, which implied that the release efficiency of solder paste needed increase. Therefore, a nanocoating stencil was proposed to further enhance quality of SPD, as the future improvement direction of experiment.

Two dimensional (2D) nanomaterials have received increasing interest because of their unique properties for versatile applications. In this work, we present a first-principles study on a new family of 2D nanostructures, Janus transition metal chalcogenide MSX (M = Ti or V; and X = C, N, Si, or P) monolayers, for their multifunctional applications. In this work, we show that the Janus MSXs possess diverse electronic and magnetic properties, and can be semiconducting or metallic, and nonmagnetic or magnetic, depending on their composition. We find that a TiSC monolayer with a 1H phase (TiSC-1H) is suitable as a cathode for Li ion batteries and anode materials for Na and Mg ion batteries due to its high open circuit voltage (OCV) (2.121 eV) for Li, and low OCVs upon Na (0.676 eV) and Mg (1.044 eV) intercalation, respectively. Importantly, TiSC-1H shows fast charge/discharge rates, good cycling stability, and high storage density as electrode materials for rechargeable batteries because of low ion diffusion barriers, small volume expansion and high specific capacity. We further show that TiSP-1H has the best performance in the hydrogen evolution reaction due to both its catalytic activities on the surfaces and relatively low overpotentials upon hydrogenation. Our study demonstrates that the 2D Janus MSXs may find multifunctional applications in nanodevices, spintronics, catalysis, and electrochemical energy storage.

Smart product-service system (PSS) has been becoming a fresh style of PSS to improve the effectiveness and efficiency of firm operations in the age of smartness. Value co-creation is taken as an attractive way to fulfil customer needs, enhance firm core competitiveness, lower environmental impacts and generate positive network externalities of platform business model. Under such circumstances, this article has proposed a value co-creation-oriented framework for smart PSS. Firstly, the structure model for smart PSS, to some extent, can cover three types of PSS. Secondly, the hierarchical value dimensions transcend the scope of traditional PSS. Furthermore, the co-creation opportunities in smart PSS are recognized. Then the value co-creation process including co-exist, co-design, co-implement and co-evaluate is proposed for smart PSS, and an illustrative case of smart fridge-service system (SFSS) is demonstrated. Finally, some limitations and future work are stated.

Ni3S2 nanowire arrays doped with vanadium(V) are directly grown on nickel foam by a facile one-step hydrothermal method. It is found that the doping can promote the formation of Ni3S2 nanowires at a low temperature. The doped nanowires show excellent electrocatalytic performance toward hydrogen evolution reaction (HER), and outperform pure Ni3S2 and other Ni3S2-based compounds. The stability test shows that the performance of V-doped Ni3S2 nanowires is improved and stabilized after thousands of linear sweep voltammetry test. The onset potential of V-doped Ni3S2 nanowire can be as low as 39 mV, which is comparable to platinum. The nanowire has an overpotential of 68 mV at 10 mA cm–2, a relatively low Tafel slope of 112 mV dec–1, good stability and high Faradaic efficiency. First-principles calculations show that the V-doping in Ni3S2 extremely enhances the free carrier density near the Fermi level, resulting in much improved catalytic activities. We expect that the doping can be an effective way to enhance...

It is a great challenge to explore cheap, abundant and eco-friendly electrocatalysts for hydrogen evolution reaction (HER). Here, we report the fabrication of VS2 nanoflowers with 1T phase by a simple hydrothermal method and their electrocatalytic performance in the HER. We find that the VS2 nanoflowers show comparable HER performance to Pt in acids, including an ultra-low onset potential of 32 mV, a Tafel slope of 34 mV dec−1 which resembles that of Pt, and a small overpotential of 58 mV (54 mV for Pt) at a current density of 10 mA cm−2. High stability and almost 100% faradaic efficiency indicate the practical application of VS2 nanoflowers in the HER. Our first-principles calculations reveal that the thermoneutral Gibbs free energy of hydrogen adsorption on both the basal and edge sites of the 1T-VS2 monolayer can be achieved under certain hydrogen coverage and the monolayer shows good conductivity, which contribute to the impressive catalytic performance of VS2 nanoflowers. We expect that the VS2 nanostructures may be applicable in electrocatalysis with high efficiency.

Photocatalytic water splitting is an environmentally friendly technique for hydrogen production. In this work, we report a novel photocatalyst consisting of two-dimensional (2D) titanium carbide (Ti2C) and graphitic carbon nitride (g-C3N4). We observe substantially enhanced water splitting activities due to the efficient synergistic interaction between Ti2C and g-C3N4. Optimal properties are achieved in the g-C3N4 with a loading of 0.4 wt% Ti2C with a hydrogen production rate of 47.5 μmol h−1, which is 14.4 times as much as that in the case using pure g-C3N4, and it even outperforms Pt-loaded g-C3N4. We further show that the Ti2C/g-C3N4 has high stability and good reproducibility. We expect that the Ti2C/g-C3N4 can be a photocatalyst for large scale applications because both Ti2C and g-C3N4 are low-cost, abundant, and nontoxic.

Quality function deployment is a cross-functional decision-making tool that converts customer needs into technical attributes of new products. Fuzzy numbers are usually adopted to evaluate the customer need importance and the customer need–technical attribute relationships. However, the weighted normalized customer need–technical attribute relationship matrix is not always full rank. If the different fuzzy numbers of two technical attributes are defined as the fuzzy negative ideal solutions, both the closeness coefficients are 0, and the traditional technique for order preference by similarity to an ideal solution cannot prioritize the two technical attributes. Actually, the rankings of different fuzzy numbers are not identical. To solve this problem, we present a new technique for order preference by similarity to an ideal solution to prioritize technical attributes in the fuzzy quality function deployment. The fuzzy positive ideal solution, fuzzy negative ideal solution, and distance measurement of the new technique for order preference by similarity to an ideal solution are improved. As a result, the proposed method not only prioritizes various forms of numbers without considering the lower and upper limits, the median, and boundary interval but also deals with the nonfull rank matrix. Besides, the Theory of Inventive Problem Solving is used to solve technical conflicts which are identified by the line-fitting method. The prioritization results from the proposed method can help to reasonably allocate design and manufacturing resources. Finally, a case on phone shell is given to illustrate the application of the proposed quality function deployment method.

Hydrogen evolution reaction (HER) is a vital step for electrochemical energy conversion technologies. However, developing cost-efficient electrocatalysts remains a huge challenge. Here, we report that Cr-doped NiSx (Cr-NiSx) in situ grown on Ni foam via a hydrothermal sulfurization reaction can be an ultra-highly efficient and low-cost electrocatalyst for HER in alkaline condition. We find that the Cr-doping can trigger the formation of NiS and NiS1.19, leading to the suppression of Ni3S2 in the nanostructure. We show that Cr-NiSx exhibits an excellent HER activity with an ultralow overpotential of 81 mV at 10 mA cm−2, better than those of most nickel sulfide catalysts, and good stability. Our combined experimental and computational study reveals that the excellent performance is contributed by: (1) stabilized NiSx phase, (2) strongly improved conductivity, (3) greatly enhanced active sites, and (4) reduced Gibbs free energy for hydrogen adsorption (ΔGH) due to the Cr-doping. We believe that this work provides a simple approach to design cost-effective and ultra-highly efficient HER electrocatalysts for practical applications.

Highly efficient noble-metal-free electrocatalysts are urgently explored for high energy density and safe metal-air batteries. Herein, an ingenious Co-Co3O4@NAC is prepared for this purpose by anchoring Co single atom on both Co3O4 nanoparticle and nitrogen-doped active carbon (NAC), where synergistic interaction among Co atoms, Co3O4 particles and NAC plays a significant role for excellent oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Moreover, the primary zinc-air battery (ZAB) with the Co-Co3O4@NAC as a cathode catalyst shows a high open circuit voltage (OCV) of 1.449 V, a specific energy density of 721 mA h/g and a maximum power density of 164 mW/cm2. The rechargeable ZAB with this catalyst displays a low voltage gap of 0.773 V at 10 mA/cm2 and stable cycling performance. This work provides a novel tactic to design elaborate high-efficient and promising bifunctional catalysts with non-noble metal atom and metal oxide for metal-air batteries.

Smart product-service system (PSS) has been transcending scope of traditional PSS and can be characterized as value co-creation business strategy. This article aims to propose a framework with hybrid approach to capture and evaluate conceptual factors of smart PSS in fuzzy front end. According to service logic that is one of value co-creation paradigms, conceptual factors can be divided into customer needs (CNs) as customer problems to be solved, co-creative value propositions (CVPs) as mutual benefits and system requirements (SRs) as abstract solutions, which just match with three spheres of customer, joint and provider in service logic, respectively. Particularly, CVPs on smart PSS are captured from various interactions in its sequence diagram. As means-end chain theory, three types of conceptual factors for smart PSS are formed into multi-hierarchy network structure, and they are evaluated through a hybrid approach integrating fuzzy DEMATEL, modified-ANP and fuzzy TOPSIS. As a result, SRs prioritization is derived to give support to conceptual design of smart PSS. Sensitivity analysis also is conducted to test reliability of SRs prioritization. Finally, an illustrative case study of smart fridge-service system (SFSS) is demonstrated along this proposed methodological framework.

Ni

Two-dimensional (2D) transition metal dichalcogenides (TMDs) have been widely used from nanodevices to energy harvesting/storage because of their tunable physical and chemical properties. In this work, we systematically investigate the effects of hydrogenation on the structural, electronic, magnetic, and catalytic properties of 33 TMDs based on first-principles calculations. We find that the stable phases of TMD monolayers can transit from 1T to 2H phase or vice versa upon the hydrogenation. We show that the hydrogenation can switch their magnetic and electronic states accompanying with the phase transition. The hydrogenation can tune the magnetic states of TMDs among non-, ferro, para-, and antiferro-magnetism and their electronic states among semiconductor, metal, and half-metal. We further show that, out of 33 TMD monolayers, 2H-TiS2 has impressive catalytic ability comparable to Pt in hydrogen evolution reaction in a wide range of hydrogen coverages. Our findings would shed the light on the multi-functional applications of TMDs.

Relaxed pure VS2 monolayer unit cell: (a) top view, (b) side view, relaxed VS2 monolayer unit cell with one side fully hydrogenated: (c) top view, (d) side view. Figure S2. Relaxed 331 supercells of VS2-Ti-doped from pure to full hydrogen coverages: (a) 0/9 or pure, (b) 1/9, (c) 2/9, (d) 3/9, (e) 4/9, (f) 5/9, (g) 6/9, (h) 7/9, (i) 8/9, (j) 9/9 or full hydrogen coverage. Figure S3. Calculated overpotentials as a function of H-coverage of VS2 with 3 dopant (Ti, W, Ni) atoms in 331 supercells. Figure S4. Calculated partial density of states of various H-covered VS2-W monolayer in 331 supercell with a hydrogen coverage at: (a) 1/9, (b) 3/9, (c) 8/9, and (d) 9/9. Figure S5. Calculated partial density of states of various H-covered VS2-W monolayer in 441 supercell with a hydrogen coverage at: (a) 2/16, (b) 5/16, (c) 14/16, and (d) 16/16. Figure S6. Calculated partial density of states of various H-covered VS2-Ni monolayer in 331 supercell with a hydrogen coverage at: (a) 1/9, (b) 3/9, (c) 8/9, and (d) 9/9. Figure S7. Calculated partial density of states of various H-covered VS2-Ni monolayer in 441 supercell with a hydrogen coverage at: (a) 2/16, (b) 5/16, (c) 14/16, and (d) 16/16. (DOC 1241 kb)